Has anyone sent an already riftborn pet back into the rift?

You toss 250,000 sP into the Rift... After a few seconds, 163,459 sP comes flying out!

Unlocked Rift Comedian! Throw a particular item in the rift

Tossed In The Rift Salad You tossed your Tossed Salad into the rift and an immediate flash of red lightning shoots out, along with your new item, Tossed In The Rift Salad.

Unlocked Rift Transformer! Have your items transformed into rift items

Not yet but I can try tomorrow

I would guess that a pet which has already been Rifted would come back as 1 of the 2 common Rift pets unless it is a species that has a specific Rift shape.

You tossed your Vind into the rift and a moment of calm is followed by a flash of red lightning, before the rift shoots out Virgo Pendant!

He's an 001 now.

I love the name 'Makeshift'.

You toss 250,000 sP into the Rift... After a few seconds, 302,401 sP comes flying out!

You tossed your into the rift and a moment of calm is followed by a flash of red lightning, before the rift shoots out !

Thank you! I named him after an obscure shape shifting transformer. seemed fitting.

Makeshift bravely steps into the Rift... and is swallowed up whole! Oh no! Maybe if you just wait a little longer...

We´ll see what happens.

Paraki bravely steps into the Rift... and is swallowed up whole! Oh no! Maybe if you just wait a little longer...

You tossed your Fried Eggs into the rift and an immediate flash of red lightning shoots out, along with your new item, Rift-Touched Eggs Sunny Side Up.

Unlocked Rift Transformer!

I threw in a common blob. So, I will see what I get in 48 hours.

You tossed your Emerald Cabochon Ring into the rift and a moment of calm is followed by a flash of red lightning, before the rift shoots out Blob Kitty Hat!

[Item=Emerald Cabochon Ring] >

You tossed your Calucko into the rift and a moment of calm is followed by a flash of red lightning, before the rift shoots out !

You toss 100,000 sP into the Rift... After a few seconds, 128,898 sP comes flying out!

I just got the Rift Comedian achievement.

the item is

Don't see it mentioned in the OP so thought it might be new...

You tossed your Soft Gray Bunny Plushie into the rift and an immediate flash of red lightning shoots out, along with your new item, Rift-Touched Bunny Plushie.

You toss 100,000 sP into the Rift... After a few seconds, 120,470 sP comes flying out!